Sealed beam high-intensity short arc lamp



June 23, 1964 N. c. BEESE SEALED BEAM HIGH-INTENSITY SHORT ARC LAMPFiled Sept. 12, 1962 I, INVENTOR. NORMAN C. BEESE United States Patent3,138,731 SEALED BEAM HIGH-INTENSITY SHORT ARC LAMP Norman C. Beese,Verona, N.J., assignor, by mesne assignments, to the United States ofAmerica as represented by the Secretary of the Navy Filed Sept. 12,1962, Ser. No. 224,593 '7 Claims. (Cl. 313- 113) The present inventionrelates to electrical discharge lamps and more particularly to highintensity short arc lamps which operate at high temperatures andpressures.

As is well known in the art, short are lamps consist generally of ananode and a cathode located within a sealed quartz envelope containing agas such as xenon, mercury, krypton, etc., which is maintained underhigh pressure of the order of about 20 atmospheres. The anode andcathode are axially aligned within the envelope and relativelypositioned with their tip ends spaced a short distance from each otherfor producing an intense arc having a very useful continuous spectrumadapting the lamp to a variety of uses.

High intensity short are lamps have not been used heretofore to anextent corresponding to their efiiciency since their use has beenlimited by some disadvantages. Difficulties have been encountered instarting the lamps since this requires high voltages and often resultsin damaging the quartz enevlope due to shock and vibration. It has alsobeen diificult to properly mount the lamp in exterior supports or bases,since the high temperatures attained during use cause the connections todeteriorate. Furthermore, these high intensity lamps are, under someconditions of use, subject to occasional explosions of the quartzenvelope which endanger persons or equipment in the proximity of thelamps.

It has been found that the various disadvantages of such high pressurelamps hereinbefore set forth may be avoided and the lamps usedeffectively by arranging the lamp unit within an enclosure formed of asealed beam type housing having relatively thick walls and providingsubstantial space with the short arc lamp structure. Such housings, asis customary, are formed of two pressed glass shells, one shell being ofparabolic shape and serving as a reflector and the other being shaped tofunction as a lens. According to the present invention, each shell ismodified to provide an integral tubular neck portion which extendsoutwardly and generally centrally therefrom for receiving the endportions of the short arc lamp unit in a manner to permit movement ofthe short are lamp unit during use. Details of accomplishing this resultwill be explained in the detailed description of the drawings.

It is an object of this invention to provide a high wattage short arcdischarge lamp construction which is arranged to minimize leakage orspark over voltages during its starting at requisite high voltages.

Another object of this invention is to provide a high wattage short aredischarge lamp construction which may be safely operated at hightemperatures and pressures.

Another object of this invention is to provide a high Wattage short aredischarge lamp which is of rugged construction and capable of eifectiveoperation under extreme impacts or sudden jars.

Other objects and advantages of the invention will become apparent fromthe detailed description read in conjunction with the accompanyingdrawings:

FIG. 1 is a view in sectional elevation of a short are envelopeassembled within a housing and showing some details.

FIG. 2 is an enlarged view on the line 2-2 of FIG. 1 to show details ofan element for mounting the short are lamp unit within the housing.

FIG. 3 is an enlarged fragmentary sectional view taken on the encircledportion of FIG. 1.

Referring to FIG. 1, the short are lamp envelope is indlcated generallyat 10, while the housing therefor or sealed beam unit is indicatedgenerally at 11. The envelope 10 of the short are lamp is constructed toform a central enlarged gaseous discharge section 12 and end sections 13and 14. An anode rod 15 of refractory material, such as tungsten, ismounted axially within the end section 13 and has an inner anode 16located within the discharge section 12 while a cathode rod 17, whichmay be formed of the same or a similar material, is mounted axially ofthe end section 14 and has a cathode 18 located within the dischargesection 12 and spaced from the anode 16 to provide a suitable arebetween the tip ends of 16 and 18. Although not shown in the drawings,the anode rod 15 and cathode rod 17 Will be understood to be sealed inthe respective end sections 13 and 14 of the envelope and the anode 16and cathode 18 may be shaped and treated as desired to provide forextended usage of the unit.

The housing 11 for the unit 10 is formed of a pressed glass shell 20which forms the lens section of the assembly and a pressed glassparabolic shell 21 which forms the reflector section of the assembly andfor this purpose has its inner face provided with a reflecting surfaceor coating 22. The shells 20 and 21 are each formed with a hollow neckportion which provides axial extensions for receiving the end portionsof the envelope 10. As shown in FIG. 1, the neck portion 23 extendsoutwardly from the shell 20 while the neck portion 24 extends outwardlyfrom the shell 21 and is positioned diametrically opposite the neckportion 23. The neck portion or extension 23 has its outer end formed toprovide a hollow stem or sleeve 25 while the outer end of the neckportion or extension 24 is provided with a similar hollow stem or sleeve26. The anode rod 15 is provided with a separate outer end portion 15'and is interconnected therewith by an expansion joint 27 which is formedof conductor material and C-shaped in order to be flexible and similarlythe cathode rod 17 has a separate outer end portion 17' which issimilarly connected with cathode rod 17 by element 28. The outer endportion 15' of the anode rod 15 is mounted in the stem or sleeve 25 infixed and sealed relation therewith while the outer end portion 17' ismounted in the stem or sleeve 26 in fixed and sealed relation therewith,consequently the expansion joints 27 and 28 permit axial movement of theenvelope 10 relative to the housing 11. In final assembly, the shells 20and 21 will have their peripheral edges fused together as indicated at29 to provide a sealed chamber including the neck portions 23 and 24.

Prior to fusing the shells 20 and 21 and in order to permit the envelope10 to move relative to the housing 11, a spring sleeve 30 is fixedlysecured between the end section 14 of the envelope 10 and the neckportion 24 of the housing 11 and a similar spring sleeve 31 is fixedlysecured between the end section 13 of the envelope 10 and the neckportion 23 of the housing 11. The spring sleeves 30 and 31 may be of anysuitable design and, for example, may take the configuration as shown inFIG. 2 in order to provide some resiliency for the lamp assembly andpermit its efficient use under shock and vibration conditions. As shown,the spring sleeve 31 of FIG. 2 is of the split ring type having an innerring or arcuate portion 40 which snugly receives the end section 13 ofthe envelope 10 and an integral outer ring or arcuate portion 41 whichis received within and is snugly pressed against the inner wall of theneck portion 23 of the housing 11. Flexible heavy current leads 42 and43 are provided for the respective anode and cathode rods through thecouplings 44 and 45.

FIG. 3 is presented to show details of one arrangement for effectingcurrent flow from the leads 42 and 43 to the anode and cathode and whichis described in my prior application Ser. No. 180,421, filed March 15,1962, for High Intensity Short Arc Lamp. This arrangement consists of aquartz coupling block 50 which is located in each end section of theenvelope 10, and for this explanation the block 50 forms a part of theanode 15. The anode 15 as shown in FIG. 3 is formed in two sections aand b which are secured in block 50 and a thin molybdenum ribbonconductor 51 has one end suitably attached to section a to extendbetween the block 50 and the inner wall of end section 13 of theenvelope and its other end positioned between the other section b ofanode rod and a quartz collar 52 mounted on section b. After assembly ofthe described elements, the end section 13 of envelope 10 will be shrunkon to the elements to provide a rigid structure. It will be understoodthat the cathode rod 17 will be assembled in end section 14 of theenvelope 10 in a similar manner.

The described lamp assembly of this invention mini mizes the developmentof shadow areas over those which would be developed if the short areenvelope 10 were to be mounted transversely of the axis of housing 11rather than longitudinally or axially thereof as shown. Since the shortare lamps shown require high voltage of the order of 15 to kv. forstarting, the design or configuration of the housing and the describedarrangement of the envelope 10 therein produce very good insulation forthe starting pulses. The spring sleeves between the short are lampenvelope and the housing provide for ready adjusting of the short areenvelope in the housing and permits proper focusing of the light sourcein order to insure good optical performance of the assembly.

In the lamp assembly shown in FIG. 1, the short arc lamp envelope 10 isideally provided with xenon gas and is designed for DC. operation andfor this purpose the cathode is disposed below the anode as is shown inthe figure. Additionally, the reflecting surface 22 is formed ofvaporized silver since this has been found to have greater beamintensity than the usual aluminized reflector surface. The lamp assemblywhich is shown in the vertical position of FIG. 1 may be used forsignalling in a horizontal direction by utilizing a plane surface mirrorset at an angle of to the light source or the lamp assembly may be usedas an omnidirectional beacon by utilizing an inverted conical reflectorof 90 apex angle disposed above the lamp source. Also the lamp assemblyof FIG. 1 may be disposed horizontally and operated with good stabilityby providing a magnetic field of suitable intensity and orientation forthe assembly.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

I claim:

quartz tubular envelope having a central gaseous discharge sectionbetween end sections, a first conductor rod disposed axially of theenvelope and in sealed relation with one end of the envelope, said firstrod having its inner end within the discharge section providing an anodeand its outer end exteriorly of the envelope, a second conductor roddisposed axially of the envelope and in a sealed relation with the otherend of the envelope, said 1. A gaseous discharge lamp and housingtherefor in V combination, said discharge lamp comprising an elongatesecond rod having its inner end within the discharge section providing acathode spaced from said anode and its outer end exteriorly of theenvelope, said housing being formed of a parabolic reflector shell and alight transmissive shell, said reflector shell having a first tubularextension centrally thereof, said transmissive shell having a secondtubular extension centrally thereof, said shells having their rim edgessecured together positioning said extensions in diametrically opposedrelation, said envelope extending axially of the housing with its endsections disposed within the tubular extensions and end portions of theconductors disposed exteriorly of the extensions, securing means fixingand sealing the conductors in the tubular extensions and an expansionjoint in at least one of said conductors permitting axial movement ofthe envelope relative to the housing.

2. The combination of discharge lamp and housing as in claim 1, furthercharacterized by means between the lamp envelope and the housing forguiding the envelope in its axial movement.

3. The combination of discharge lamp and housing as in claim 1, furthercharacterized by a first sleeve means between one end section of thelamp envelope and the first tubular extension of the housing and asecond sleeve means between the other end section of the envelope andthe second tubular extension of the housing for guiding the envelope inits axial movement.

4. The combination of discharge lamp and housing as in claim 3, furthercharacterized by said first and second sleeve means each comprising aninner ring for snugly receiving an end section of the lamp envelope andan integral outer ring for reception within a tubular extension in snugengagement with its inner wall.

5. The combination of discharge lamp and housing as in claim 1, furthercharacterized by said expansion joint being formed of conductor materialwhich is generally C-shaped to provide flexibility and connected toseparate sections of said one conductor.

6. The combination of discharge lamp and housing as in claim 1, furthercharacterized by said securing means for fixing and sealing theconductors in the tubular extensions comprising a hollow stem formed inthe end of each extension.

7. The combination of discharge lamp and housing as in claim 1, furthercharacterized by the parabolic reflector shell having its inner surfacecoated with vaporized silver.

Thouret Mar. 7, 1961 Story Dec. 17, 1963

1. A GASEOUS DISCHARGE LAMP AND HOUSING THEREFOR IN COMBINATION, SAIDDISCHARGE LAMP COMPRISING AN ELONGATE QUARTZ TUBULAR ENVELOPE HAVING ACENTRAL GASEOUS DISCHARGE SECTION BETWEEN END SECTIONS, A FIRSTCONDUCTOR ROD DISPOSED AXIALLY OF THE ENVELOPE AND IN SEALED RELATIONWITH ONE END OF THE ENVELOPE, SAID FIRST ROD HAVING ITS INNER END WITHINTHE DISCHARGE SECTION PROVIDING AN ANODE AND ITS OUTER END EXTERIORLY OFTHE ENVELOPE, A SECOND CONDUCTOR ROD DISPOSED AXIALLY OF THE ENVELOPEAND IN SEALED RELATION WITH THE OTHER END OF THE ENVELOPE, SAID SECONDROD HAVING ITS INNER END WITHIN THE DISCHARGE SECTION PROVIDING ACATHODE SPACED FROM SAID ANODE AND ITS OUTER END EXTERIORLY OF THEENVELOPE, SAID HOUSING BEING FORMED OF A PARABOLIC REFLECTOR SHELL AND ALIGHT TRANSMISSIVE SHELL, SAID REFLECTOR SHELL HAVING A FIRST TUBULAREXTENSION CENTRALLY THEREOF, SAID TRANSMISSIVE SHELL HAVING A SECONDTUBULAR EXTENSION CENTRALLY THEREOF, SAID SHELLS HAVING THEIR RIM EDGESSECURED TOGETHER POSITIONING SAID EXTENSIONS IN DIAMETRICALLY OPPOSEDRELATION, SAID ENVELOPE EXTENDING AXIALLY OF THE HOUSING WITH ITS ENDSECTIONS DISPOSED WITHIN THE TUBULAR EXTENSIONS AND END PORTIONS OF THECONDUCTORS DISPOSED EXTERIORLY OF THE EXTENSIONS, SECURING MEANS FIXINGAND SEALING THE CONDUCTORS IN THE TUBULAR EXTENSIONS AND AN EXPANSIONJOINT IN AT LEAST ONE OF SAID CONDUCTORS PERMITTING AXIAL MOVEMENT OFTHE ENVELOPE RELATIVE TO THE HOUSING.